// Copyright (c) 2008 Davy Brion (ralinx@davybrion.com)
// All rights reserved.
// 
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
// 
//     * Redistributions of source code must retain the above copyright notice,
//       this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright notice,
//       this list of conditions and the following disclaimer in the documentation
//       and/or other materials provided with the distribution.
//     * Neither the name of Davy Brion nor the names of the
//       contributors may be used to endorse or promote products derived from this
//       software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

using System;
using System.Collections.Generic;
using System.Linq;

using Albatross.Common;
using Albatross.Common.Messaging;

namespace Albatross.ClientSide.Messaging
{
	public class Dispatcher : Disposable, IDispatcher
	{
		private Dictionary<string, Type> keyToTypes;
		private readonly IRequestProcessor requestProcessor;
		private Dictionary<string, int> keyToResultPositions;
		private List<Request> requests;
		private Response[] responses;

		public Dispatcher( IRequestProcessor requestProcessor )
		{
			this.requestProcessor = requestProcessor;
			InitializeState();
		}

		public IEnumerable<Request> Requests
		{
			get
			{
				return requests;
			}
		}

		public IEnumerable<Response> Responses
		{
			get
			{
				return responses;
			}
		}

		public virtual void Add( params Request[] requestsToAdd )
		{
			foreach ( var request in requestsToAdd )
			{
				Add( request );
			}
		}

		public virtual void Add( Request request )
		{
			AddRequest( request, false );
		}

		public virtual void Add( string key, Request request )
		{
			AddRequest( request, true );
			keyToTypes[ key ] = request.GetType();
			keyToResultPositions[ key ] = requests.Count - 1;
		}

		public virtual TResponse Get<TResponse>() where TResponse : Response
		{
			SendRequestsIfNecessary();
			var responseType = typeof( TResponse );
			return ( TResponse )responses.First( r => r.GetType().Equals( responseType ) );
		}

		public virtual TResponse Get<TResponse>( string key ) where TResponse : Response
		{
			SendRequestsIfNecessary();
			return ( TResponse )responses[ keyToResultPositions[ key ] ];
		}

		public virtual TResponse Get<TResponse>( Request request ) where TResponse : Response
		{
			return ( TResponse )GetResponses( request )[ 0 ];
		}

		public virtual void Clear()
		{
			InitializeState();
		}

		protected override void DisposeManagedResources()
		{
			if ( requestProcessor != null )
				requestProcessor.Dispose();
		}

		protected virtual Response[] GetResponses( params Request[] requestsToProcess )
		{
			//var dotNetRequests = requestsToProcess.OfType<DotNetRequest>();

			//if ( dotNetRequests != null && dotNetRequests.Count() == requestsToProcess.Count() )
			//{
			//	return requestProcessor.Process( dotNetRequests.ToArray() );
			//}

			return requestProcessor.Process( requestsToProcess );
		}


		


		private void SendRequestsIfNecessary()
		{
			if ( responses == null )
			{
				responses = GetResponses( requests.ToArray() );
			}
		}

		private void AddRequest( Request request, bool wasAddedWithKey )
		{
			Type requestType = request.GetType();

			if ( RequestTypeIsAlreadyPresent( requestType ) &&
				( RequestTypeIsNotAssociatedWithKey( requestType ) || !wasAddedWithKey ) )
			{
				throw new InvalidOperationException( String.Format( "A request of type {0} has already been added. "
					+ "Please add requests of the same type with a different key.", requestType.FullName ) );
			}

			requests.Add( request );
		}

		private bool RequestTypeIsNotAssociatedWithKey( Type requestType )
		{
			return !keyToTypes.Values.Contains( requestType );
		}

		private bool RequestTypeIsAlreadyPresent( Type requestType )
		{
			return Requests.Count( r => r.GetType().Equals( requestType ) ) > 0;
		}

		private void InitializeState()
		{
			requests = new List<Request>();
			responses = null;
			keyToTypes = new Dictionary<string, Type>();
			keyToResultPositions = new Dictionary<string, int>();
		}

	}
}